Welcome to TeX.SX! Please help us to help you and add a minimal working example (MWE) that illustrates your problem. It will be much easier for us to reproduce your situation and find out what the issue is when we see compilable code, starting with \documentclass{...} and ending with \end{document}.
– user31729Jan 18 '15 at 10:29

Which error does TeX spill out? Did you use \usepackage{fancybox} ? And do you really nead a frame around \shadowbox?
– user31729Jan 18 '15 at 10:30

i m not using \usepackage{fancybox}, i m new to latex and i want to draw a simple text-box having a shadow border at its left side. i m not understanding how to code this in latex.
– sadafJan 18 '15 at 10:39

Try to use my provided answer as a starting point. And change \bf to \textbf{...} since \bf is deprecated syntax
– user31729Jan 18 '15 at 10:43